1. Field of the Invention
The present invention relates to a manufacturing method of a keypad for a mobile phone and the keypad manufactured thereby, and more particularly to a method for manufacturing a keypad which can provide a transparent or translucent marking portion (such as a number, a character, or a symbol of the key) with an elegant metallic glossy image, and present various color images when light is emitted, by attaching a vacuum deposition layer and a cellophane paper to a lower surface of a key in the keypad of the mobile phone.
2. Description of the Related Art
In general, “portable communication devices” refers to devices that are portable and enable the users of the devices to perform wireless communications. Portable communication devices include an HHP (hand-held phone), a CT-2 (cordless telephone 2) cellular phone, a digital phone, a PCS (personal communication system) phone, and a PDA (personal digital assistant), and are classified into various types according to their external appearance. For example, mobile phones are classified into bar-type, flip-type, folder-type, and slide-type mobile phones according to their external appearance. The above-mentioned conventional mobile phones necessarily include an antenna unit, a data input/output unit, and a data transceiver. A keypad for enabling the user to input data through a pressing operation using his/her fingers is generally used as the data input unit, and includes a plurality of keys arranged thereon.
The structure of a mobile phone including a keypad 1 will now be described with reference to FIG. 1. A plurality of keys 4, each of which includes a transparent or translucent marking portion 3 for displaying a number, a character, or a symbol, are constructed on an elastic pad 2 so that the user may easily identify operational functions and touch a key to input a desired operational signal.
The key 4 secures a desired color and durability through the spraying, coating, and printing processes performed with respect to the upper surface of the key body 5 (see FIG. 3) of a transparent or translucent resin material (see FIG. 2). In addition, in order to increase marking resolution of numerals, characters, and symbols, a laser etching process is performed adaptively to the transparent or translucent marking portion 3, so that light generated by a light emitting unit 11 installed on a printed circuit board 10 can be easily transmitted through the transparent or translucent marking portion 3, thereby remarkably displaying the transparent or translucent marking portion 3.
The manufacturing method of the key 4 will now be described with reference to FIGS. 2 and 3.
First, a color paint for forming a transparent or translucent marking background color paint layer 6 for the transparent or translucent marking portion 3 is coated onto the key body 5 made of a transparent or translucent resin material, and then an opaque paint layer 7 is coated so as to prevent light from being transmitted through portions other than the transparent or translucent marking portion 3.
For the opaque paint layer 7, a black paint is generally used in consideration of a light absorbing characteristic and a laser workability characteristic. If a key background has a color of the black series or gray series, it is possible to omit the process of coating the opaque paint layer 7. Thereafter, a second color key background paint layer 8 for presentation of a key background color is coated. Then, in order to form the transparent or translucent marking portion 3, a laser etching process is performed adaptively to the shape of a numeral, a character, or a symbol, so that the second color paint layer 8 for a key background color and the opaque paint layer 7 may be removed, and only the first marking color paint layer 6 for forming the transparent or translucent marking portion will remain at the corresponding laser-etched portion, thereby enabling light, which has been generated by the light emitting unit 11 installed on the printed circuit board 10, to be transmitted through the corresponding portion. Finally, a high-hardness transparent coating layer 9 is coated onto the surface of the key 4 so as to secure hardness of the surface and improve abrasion resistance thereof.
Meanwhile, the construction of the coating layers 7 and 8 varies depending on the key background color. That is, when the key background color is a light color such as white, generally a silver paint layer (not shown) is formed between the opaque paint layer 7 and the key background color paint layer 8 so as to prevent the light background color from being dark due to the opaque paint layer 7 of a black color.
However, although a high-hardness transparent or translucent coating layer is formed as the last layer for a key in order to secure hardness of the key surface in the prior art, an abrasion phenomenon happens due to the use of the key after a predetermined period has passed, so that the high-hardness transparent coating layer, the key background color paint layer, and a transparent or translucent marking portion, which have been formed on the upper portion of the key, wear away.
In addition, according to the conventional key manufacturing method, since a color is presented by a method of spraying/coating each of the paint layers on the upper surface of the key, it is impossible to present an elegant metallic gloss. Also, according to the conventional key manufacturing method, since the transparent or translucent marking portion is constructed with only one color paint layer, such as green, red, white, etc., it is impossible to present various colors and effects when the keypad emits light.